The present invention relates to a space light modulating apparatus, a process for manufacturing a microstructure element used in the space light modulating apparatus, a microstructure element manufactured by the process, and a projector including the space light modulating apparatus, and more particularly, to a liquid crystal space light modulating apparatus.
A dot-matrix image display is one of the popular image displays currently in use, such as a liquid crystal panel (liquid crystal display), a cathode ray tube (CRT) display, and a plasma display. The dot-matrix image display represents an image by using a number of pixels that are two-dimensionally arranged in a cyclic manner. In this case, so-called sampling noise tends to occur due to the cyclic alignment structure, resulting in degradation in the image quality (images with a rough texture). A method to reduce such degradation in the image quality is disclosed in, for example, Japanese Patent Application Laid-Open Publication No. 8-122709.
In the dot-matrix image display, a light-shielding part, referred to as a black matrix, is formed in an area between pixels to reduce unnecessary light. However, in recent years, the application mode of the image display has been increasing cases in which people watch a large screen from a comparatively short distance. For this reason, the viewers sometimes recognize an image of the black matrix. Consequently, the conventional dot-matrix image display offers an image of deteriorated image quality, such as an image with less smoothness or rough texture, because of the black matrix image. The technology described in the above patent document can hardly reduce the degradation in the image quality due to the black matrix image.
A method to prevent the viewer from recognizing a light-shielding area such as the black matrix is to input light from an image display onto a group of prisms. The flat portion of the prisms transmits the light from the image display as it is. Refracting surfaces of the prisms refract the light from the image display. The light passed through the prisms generates lights that are deflected by the refracting surfaces of the prisms in addition to lights that proceeded straight through the flat portion. The lights deflected form a pixel image on the black matrix, making it possible to reduce recognition of the black matrix.
Each of prism elements that constitute the group of prisms is formed into a fine shape in micrometers. In conventional technologies, the prism element is manufactured by carrying out a cutting process on a predetermined area. In this case, even with the same machining data, it is difficult to repeatedly form prism elements having a desired shape within the predetermined area for the following three reasons. Firstly, repetitive positioning accuracy of a cutting machine for the cutting process is insufficient. When the repetitive positioning accuracy is insufficient, it becomes difficult to form the fine shape in a desired position. Secondly, a servo mechanism, which controls positioning of the machining device, is easily influenced by various disturbances such as temperature, atmospheric pressure, and vibration. The third reason is that it is difficult to adjust a positional relation between a cutting tool of the machining device and a workpiece with sub-micron precision, while the relative position inside the machining device itself is controlled in a nano-scale to allow machining processes with high precision.
For example, FIG. 39 is a cross-section of a workpiece with a flat plate on which fine V-shaped grooves are formed by a conventional technology. The machining process is started at position A of the flat plate 1300, and finished at position B. In this case, when the servo mechanism of the machining device is affected by any disturbance such as temperature, atmospheric pressure, or vibration, the surface of the machining side is formed into a curved surface as shown by a dot line 1301. Therefore, when the servo mechanism is affected by an external environment (disturbance), it becomes difficult to form a desired shape with sufficient precision. This kind of problem becomes more conspicuous when a fine-shape element has not a simple shape, but an irregular shape. Moreover, when manufacturing the fine-shape element, it is also difficult to carry out multiple machining processes at the same portion of the workpiece.
The present invention is to solve the above problems. The object of the present invention is to provide a space light modulating apparatus and a projector that provide smooth image quality without the light-shielding area, such as the black matrix, being recognized.
In addition, another object of the present invention is to provide a process for manufacturing a microstructure element with a desired fine-shape accurately independent of the external environment, a microstructure element manufactured by the process, a space light modulating apparatus employing the microstructure, and a projector employing the space light modulating apparatus.